(x+3y)*(x-3y)-x^2 упростить

Question

(x+3y)*(x-3y)-x^2 упростить

Answer 1

(x+3y)(x-3y)-x^2=x^2-9y^2-x^2=-9y^2

Answer 2

х+3у* х-3у - х:2

 1х:1х+1х= -3у+3у:2

2х=0